Add GetMeta to database storage interface

database/controller.go

@@ -42,7 +42,7 @@ func (c *Controller) Injected() bool {
 	return c.storage.Injected()
 }
 
-// Get return the record with the given key.
+// Get returns the record with the given key.
 func (c *Controller) Get(key string) (record.Record, error) {
 	if shuttingDown.IsSet() {
 		return nil, ErrShuttingDown
@@ -76,6 +76,28 @@ func (c *Controller) Get(key string) (record.Record, error) {
 	return r, nil
 }
 
+// Get returns the metadata of the record with the given key.
+func (c *Controller) GetMeta(key string) (*record.Meta, error) {
+	if shuttingDown.IsSet() {
+		return nil, ErrShuttingDown
+	}
+
+	m, err := c.storage.GetMeta(key)
+	if err != nil {
+		// replace not found error
+		if err == storage.ErrNotFound {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+
+	if !m.CheckValidity() {
+		return nil, ErrNotFound
+	}
+
+	return m, nil
+}
+
 // Put saves a record in the database, executes any registered
 // pre-put hooks and finally send an update to all subscribers.
 // The record must be locked and secured from concurrent access

database/interface.go

@@ -201,6 +201,40 @@ func (i *Interface) getRecord(dbName string, dbKey string, mustBeWriteable bool)
 	return r, db, nil
 }
 
+func (i *Interface) getMeta(dbName string, dbKey string, mustBeWriteable bool) (m *record.Meta, db *Controller, err error) {
+	if dbName == "" {
+		dbName, dbKey = record.ParseKey(dbKey)
+	}
+
+	db, err = getController(dbName)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	if mustBeWriteable && db.ReadOnly() {
+		return nil, db, ErrReadOnly
+	}
+
+	r := i.checkCache(dbName + ":" + dbKey)
+	if r != nil {
+		if !i.options.hasAccessPermission(r) {
+			return nil, db, ErrPermissionDenied
+		}
+		return r.Meta(), db, nil
+	}
+
+	m, err = db.GetMeta(dbKey)
+	if err != nil {
+		return nil, db, err
+	}
+
+	if !m.CheckPermission(i.options.Local, i.options.Internal) {
+		return nil, db, ErrPermissionDenied
+	}
+
+	return m, db, nil
+}
+
 // InsertValue inserts a value into a record.
 func (i *Interface) InsertValue(key string, attribute string, value interface{}) error {
 	r, db, err := i.getRecord(getDBFromKey, key, true)
@@ -236,7 +270,7 @@ func (i *Interface) Put(r record.Record) (err error) {
 	// get record or only database
 	var db *Controller
 	if !i.options.HasAllPermissions() {
-		_, db, err = i.getRecord(r.DatabaseName(), r.DatabaseKey(), true)
+		_, db, err = i.getMeta(r.DatabaseName(), r.DatabaseKey(), true)
 		if err != nil && err != ErrNotFound {
 			return err
 		}
@@ -247,7 +281,7 @@ func (i *Interface) Put(r record.Record) (err error) {
 		}
 	}
 
-	// Check if database is read only before we add to the cache.
+	// Check if database is read only.
 	if db.ReadOnly() {
 		return ErrReadOnly
 	}
@@ -274,7 +308,7 @@ func (i *Interface) PutNew(r record.Record) (err error) {
 	// get record or only database
 	var db *Controller
 	if !i.options.HasAllPermissions() {
-		_, db, err = i.getRecord(r.DatabaseName(), r.DatabaseKey(), true)
+		_, db, err = i.getMeta(r.DatabaseName(), r.DatabaseKey(), true)
 		if err != nil && err != ErrNotFound {
 			return err
 		}
@@ -285,6 +319,11 @@ func (i *Interface) PutNew(r record.Record) (err error) {
 		}
 	}
 
+	// Check if database is read only.
+	if db.ReadOnly() {
+		return ErrReadOnly
+	}
+
 	r.Lock()
 	if r.Meta() != nil {
 		r.Meta().Reset()
@@ -328,6 +367,13 @@ func (i *Interface) PutMany(dbName string) (put func(record.Record) error) {
 		}
 	}
 
+	// Check if database is read only.
+	if db.ReadOnly() {
+		return func(r record.Record) error {
+			return ErrReadOnly
+		}
+	}
+
 	// start database access
 	dbBatch, errs := db.PutMany()
 	finished := abool.New()
@@ -462,6 +508,11 @@ func (i *Interface) Delete(key string) error {
 		return err
 	}
 
+	// Check if database is read only.
+	if db.ReadOnly() {
+		return ErrReadOnly
+	}
+
 	i.options.Apply(r)
 	r.Meta().Delete()
 	return db.Put(r)
@@ -495,6 +546,11 @@ func (i *Interface) Purge(ctx context.Context, q *query.Query) (int, error) {
 		return 0, err
 	}
 
+	// Check if database is read only before we add to the cache.
+	if db.ReadOnly() {
+		return 0, ErrReadOnly
+	}
+
 	return db.Purge(ctx, q, i.options.Local, i.options.Internal)
 }
 

database/query/README.md

@@ -22,7 +22,7 @@ Please note that some feeders may have other special characters. It is advised t
 ## Operators
 
 | Name                    | Textual            | Req. Type | Internal Type | Compared with             |
-|---|---|---|---|
+|-------------------------|--------------------|-----------|---------------|---------------------------|
 | Equals                  | `==`               | int       | int64         | `==`                      |
 | GreaterThan             | `>`                | int       | int64         | `>`                       |
 | GreaterThanOrEqual      | `>=`               | int       | int64         | `>=`                      |
@@ -38,11 +38,11 @@ Please note that some feeders may have other special characters. It is advised t
 | StartsWith              | `startswith`, `sw` | string    | string        | `strings.HasPrefix()`     |
 | EndsWith                | `endswith`, `ew`   | string    | string        | `strings.HasSuffix()`     |
 | In                      | `in`               | string    | string        | for loop with `==`        |
-| Matches | `matches`, `re` | string | int64 | `regexp.Regexp.Matches()` |
+| Matches                 | `matches`, `re`    | string    | string        | `regexp.Regexp.Matches()` |
 | Is                      | `is`               | bool*     | bool          | `==`                      |
 | Exists                  | `exists`, `ex`     | any       | n/a           | n/a                       |
 
-\*accepts strings: 1, t, T, TRUE, true, True, 0, f, F, FALSE
+\*accepts strings: 1, t, T, true, True, TRUE, 0, f, F, false, False, FALSE
 
 ## Escaping
 

database/registry.go

@@ -25,7 +25,7 @@ var (
 	registry     = make(map[string]*Database)
 	registryLock sync.Mutex
 
-	nameConstraint = regexp.MustCompile("^[A-Za-z0-9_-]{4,}$")
+	nameConstraint = regexp.MustCompile("^[A-Za-z0-9_-]{3,}$")
 )
 
 // Register registers a new database.
@@ -56,7 +56,7 @@ func Register(new *Database) (*Database, error) {
 	} else {
 		// register new database
 		if !nameConstraint.MatchString(new.Name) {
-			return nil, errors.New("database name must only contain alphanumeric and `_-` characters and must be at least 4 characters long")
+			return nil, errors.New("database name must only contain alphanumeric and `_-` characters and must be at least 3 characters long")
 		}
 
 		now := time.Now().Round(time.Second)

database/storage/badger/badger.go

@@ -82,6 +82,18 @@ func (b *Badger) Get(key string) (record.Record, error) {
 	return m, nil
 }
 
+// GetMeta returns the metadata of a database record.
+func (b *Badger) GetMeta(key string) (*record.Meta, error) {
+	// TODO: Replace with more performant variant.
+
+	r, err := b.Get(key)
+	if err != nil {
+		return nil, err
+	}
+
+	return r.Meta(), nil
+}
+
 // Put stores a record in the database.
 func (b *Badger) Put(r record.Record) (record.Record, error) {
 	data, err := r.MarshalRecord(r)

database/storage/bbolt/bbolt.go

@@ -96,6 +96,18 @@ func (b *BBolt) Get(key string) (record.Record, error) {
 	return r, nil
 }
 
+// GetMeta returns the metadata of a database record.
+func (b *BBolt) GetMeta(key string) (*record.Meta, error) {
+	// TODO: Replace with more performant variant.
+
+	r, err := b.Get(key)
+	if err != nil {
+		return nil, err
+	}
+
+	return r.Meta(), nil
+}
+
 // Put stores a record in the database.
 func (b *BBolt) Put(r record.Record) (record.Record, error) {
 	data, err := r.MarshalRecord(r)

database/storage/fstree/fstree.go

@@ -104,6 +104,18 @@ func (fst *FSTree) Get(key string) (record.Record, error) {
 	return r, nil
 }
 
+// GetMeta returns the metadata of a database record.
+func (fst *FSTree) GetMeta(key string) (*record.Meta, error) {
+	// TODO: Replace with more performant variant.
+
+	r, err := fst.Get(key)
+	if err != nil {
+		return nil, err
+	}
+
+	return r.Meta(), nil
+}
+
 // Put stores a record in the database.
 func (fst *FSTree) Put(r record.Record) (record.Record, error) {
 	dstPath, err := fst.buildFilePath(r.DatabaseKey(), true)

database/storage/hashmap/map.go

@@ -44,6 +44,18 @@ func (hm *HashMap) Get(key string) (record.Record, error) {
 	return r, nil
 }
 
+// GetMeta returns the metadata of a database record.
+func (hm *HashMap) GetMeta(key string) (*record.Meta, error) {
+	// TODO: Replace with more performant variant.
+
+	r, err := hm.Get(key)
+	if err != nil {
+		return nil, err
+	}
+
+	return r.Meta(), nil
+}
+
 // Put stores a record in the database.
 func (hm *HashMap) Put(r record.Record) (record.Record, error) {
 	hm.dbLock.Lock()

database/storage/injectbase.go

@@ -11,7 +11,8 @@ import (
 )
 
 var (
-	errNotImplemented = errors.New("not implemented")
+	// ErrNotImplemented is returned when a function is not implemented by a storage.
+	ErrNotImplemented = errors.New("not implemented")
 )
 
 // InjectBase is a dummy base structure to reduce boilerplate code for injected storage interfaces.
@@ -22,22 +23,27 @@ var _ Interface = &InjectBase{}
 
 // Get returns a database record.
 func (i *InjectBase) Get(key string) (record.Record, error) {
-	return nil, errNotImplemented
+	return nil, ErrNotImplemented
+}
+
+// Get returns a database record.
+func (i *InjectBase) GetMeta(key string) (*record.Meta, error) {
+	return nil, ErrNotImplemented
 }
 
 // Put stores a record in the database.
 func (i *InjectBase) Put(m record.Record) (record.Record, error) {
-	return nil, errNotImplemented
+	return nil, ErrNotImplemented
 }
 
 // Delete deletes a record from the database.
 func (i *InjectBase) Delete(key string) error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Query returns a an iterator for the supplied query.
 func (i *InjectBase) Query(q *query.Query, local, internal bool) (*iterator.Iterator, error) {
-	return nil, errNotImplemented
+	return nil, ErrNotImplemented
 }
 
 // ReadOnly returns whether the database is read only.

database/storage/interface.go

@@ -13,6 +13,7 @@ import (
 type Interface interface {
 	// Primary Interface
 	Get(key string) (record.Record, error)
+	GetMeta(key string) (*record.Meta, error)
 	Put(m record.Record) (record.Record, error)
 	Delete(key string) error
 	Query(q *query.Query, local, internal bool) (*iterator.Iterator, error)

database/storage/sinkhole/sinkhole.go

@@ -44,6 +44,11 @@ func (s *Sinkhole) Get(key string) (record.Record, error) {
 	return nil, storage.ErrNotFound
 }
 
+// GetMeta returns the metadata of a database record.
+func (s *Sinkhole) GetMeta(key string) (*record.Meta, error) {
+	return nil, storage.ErrNotFound
+}
+
 // Put stores a record in the database.
 func (s *Sinkhole) Put(r record.Record) (record.Record, error) {
 	return r, nil